Diagnosis Conditions

Air flow rate from 25 to 120 kg/h
Oxygen sensing after TWC is active
Basic adaptation has reached steady condition
No secondary air diagnosis
No fuel tank ventilation diagnosis
EVAP canister not highly loaded
No fault in EVAP canister purge valve, fuel tank ventilation system, secondary air injection, oxygen sensor heating after TWC, RPM/crankshaft position sensor and fuel supply system.

Fig 1: DTC P0139 & P0159 Fault Conditions

Courtesy of PORSCHE OF NORTH AMERICA, INC.